Clamp and switch for high power incandescent lamps



1953 R. J. BRANDT 2,859,291

CLAMP AND SWITCH FOR HIGH POWER INCANDESCENT LAMPS Filed April 1, 1957 2Sheets-Sheet 1 ROBERT JAY BRANDT,

INVENTOR.

HUEBNER,BEEHLER SWORREL,

ATTORNEYS.

R. J. BRANDT 2,859,291

CLAMP AND SWITCH FOR HIGH POWER INCANDESCENT LAMPS Nov. 4, 1958 2Sheets-Sheet 2 Filed April 1, 1957 ROBERT JAY BRAND];

INVENTOR.

HUEBNER, BEEHLER 8! WORREL j A T'TORNEKS.

United States Patent Ofi ice 2,859,291 Patented Nov. 4, 1-958"CLAMPANDSWITCH FOR HIGH POWE INCANDESCENT LAMPS :Robert JayBrandt, LosAngeles, Calif. Application April 1, 1957, serialNo. 650,028 90mm. Cl.200- 51 The invention relates .to lamp sockets especially adapted 'forhigh :power incandescent lamps :and has particular reference to anautomatic sequence clamp and switch device by-means of which:thefcontact prongs Whichconveynthe electric current Ltrom a lamp socketto a lamp are'simultaneously clamped and then interconnected with theelectric circuit.

Very large incandescent lampsus'ed primarily 'for high powerillumination are ordinarily constructed with contact' elementscomprising prongs which "protrude downwardly 'ifrom 1116 'base ofth'elamp into suitable recesses formed in'a'pair of blocks in-a lampreceptacle or socket. Gontact clamps are provided in the blocks andserve to fasten about the prongs .prior to passing a heavy current tothe lamp. "It'frequently happens that technicians handling suchequipment often insert the prongs into the recesses "and neglect totighten the clamping means upon the prongs prior to switching on thecurrent. As a'result, because of the very heavy electric chargeinvolved,'there results a considerable arcing 'between the clamps andthe prongs. Repeated arcing of this kind pits the surfaces of theprongs, which pitting interferes with .the making of a goodelectticcontact causing increasing itrouble with the equipment and an attendantlossof time and expense.

It is *therefore among the objects of the'invention to provide a new.and improved lamp socket for high power incandescent lamps of the prongcontact type which is effective :in "insuring against arcingat theprongs.

Another object ;of the invention is to provide a new and improved dampsocket for-high power plug contact lamps so arranged that .a circuit .tothe prongs remains open against :flow of electricity to the lamp untilthe prongs have been properly clamped. 4

:Another o'bject :is to provide a socket for prong-contact electriclamps of'hig'h 'powerwhichxis proof against the :passing of electriccurrent to the lamp before the prongsware.properlysclamped andwhich alsois of such eonstructionzthat the clamping de'viceis readily released andthe 'circuit readily broken whenever .the clamp is removed fromzthesocket.

Still :another object of the invention is to provide a rugged andinexpensive socket for prong 'contactelectric lamps =whichincorporatesdna socket otherwise of standard; :size and wonstruction "a switch:meanscoupled to the clamping device in such sequence that the switch cannot-be-Tclosed "until proper clamping :ha been completed.

With these and other objects in view, the invention consists :in theconstruction, arrangement and combination a of -the various parts of-the device whereby the objec'ts contemplated are attained, as Ihereinafter 'set forth, pointedout in the appended claims andillustrated in the accompanying drawings.

Invthe drawings:

Figure 1 is a side elevational view -of a lamp and socket mountedforaoperati'on.

Figure 2 is :a cross-sectional view taken on the line 2'-2iof-.'Fig'urel. D

Figure 3 is an exploded view 40f :the clamping and switching elements.

Figure -4 is a cross-sectional view-through the socket showing theclamping --and switching means in off or open-position.

:Figure 15 isia fragmentary vertical sectional view taken 1 n the line55 of Figure 4.

Figure 6 is a-fragmentary vertical sectional view taken on the line 66of Figure 4.

Figure 7 is a fra'gr'ne'ntarycross-sectional view similar to the rightportion of the view :of Figure 4 showing the position of partsimmediately after movement has begun toward a closed or on position.

Figure 8 is a fragmentary cross-sectional view similar to Figure 7showing the parts -in on and clamped position.

-In an embodiment of the inventionchosen for the purpose of illustrationthere is shown an incandescent lamp 10 having a base 11 from'the lowerend of which 'protrudes contact prongs 1-2 and 13. ]It will be notedfrom the character of filaments 1'4 indicated that the 'lamp here underconsideration is one of exceedingly high power and of a type frequentlyused in outdoor lighting and in motion picture and TVsets where a greatdeal-of luminescence is required. In Figure 1 the lamp 10 is shownmounted in a socket 15 which in turn'is carried upon a chassis 16. Anelectric lead 17 from a suitable source'of supply communicates withacontrol switch 18 from which wires 19 and '20 extend to binding posts 21and 22"respective1y of the socket 15.

More particularly the socket includes a housing 25 here shown with arectangular shape at the upper end of which are four resilientbr'acketst'hree of which are shown indicated by the reference characters26, 27 and 28, which "are' adapted -to grasp "and steady the base of thelamp, thereby to assist in holdingit inplace.

The housing '25 has an interior chamber 29 within which'are'position'ed'blocks'30 and "31 of dielectric'rnaterial, the blocksbeing slightly smaller in size than the chamber 29 and tightenedin-place by meansof set screws 32. These blocks when t'igh-tenedfinplace provide a pair of prong-receiving recesses 33 and 34.

'The blocks 30 and 31 are matching blocks so constructed that the block30 contains matchi n'g'halves and 36, respectively, of recesses 33 and"34(Simi1afly block 31 carries matching halves 37 and 38,'respectively,of recesses '33 and 34. To maintain the blo'c'ks'in proper relationshipone with respect'to the other, projections 39 and 40 are' provided inthe block30 adapted to be received in corresponding'holesffl and 4'2 inthe block 31.

In the prong-receiving recess '33 aremetallic liners or 1iner halves 4'3and. It-will'-*be note'dthat the outside radius of the liners "issomething less than the inside radius of the'corresponding recess '33and'that the liners are something less than 'a*semi-circle. The linershave hdllows43' and -44', respectively,;ad'apted to surround the prong12. Both *of'the 'liners 4 3 and-44 have solid 'bottoms, as'-shown"togood-advantage {in Figure 3, the liner 43 extending'downwardly to alocation lower than the bottom ofth'eliner 4'4,-'thereby to provide abase for the binding post 22. "In the "solid bottom "portions are holes47 and 48 adapted to-slideover the;projection 39, thereby to 1101s theliners 'in position Within "the prong-receiving recess 33. A cut-outportion 46in the block 31 gives ac cess to 'the b'indingpost 2"1:and acut-out portion 49 gives access to the binding post 22.

Similarly liners 5 0 and "Slate provided for matching I halves 36' and38', respectively, *of the prong-receiving recess '34. The outside andinside radius of curvature on the liners 50-and5 1 are relativelythes'ame as corresponding outside and insi'd'e radii of curvature of theliners 43 and 44. These'liners'SO and51 also have solid bottom portionsin which are holes 52 and 53, respectively, adapted to 'receive theprojection 40, thereby 'to hold the liners 'in position. .Of specialinterest is a laterally extending switch-contact plate or 'armature 54ontheliner 50 which is:adapted -to:lie within a plate recess 55 in .theblock 31.

Also lying within the plate recess 55 is a second switch 3 armature 56of somewhat. composite construction, the lower portion 57 of whichprovides a mounting for the binding post 21. A threaded hole 58 in thelower por tion provides means for attachment of a screw 59 to hold thearmature in proper position. Comprising part of the armature 56 is apair of resilient arms 60 and 61 which act together to form one of thecontact points of the switch indicated generally by the referencecharacter 62. In the block 31 there is provided a plug aperture 63communicating with the prong-receiving recess 33 and a plug-receivingaperture 64 communicating with the prong-receiving recess 34. A plug 65of dielectric material lies within the recess 63 and a similar plug 66lies within the recess 64. The plugs in each instance have a bearingupon the respective liners 44 and 51. Still another plug aperture 67 inthe block 31 communicates with the plate recess 55. Within the lastidentified plug aperture 67 is a plug68 also of dielectric material.

To manipulate the plugs, therebyto tighten a grip upon the prongs 12 and13 and to manipulate the switch 62, there is provided a toggle switchindicated generally by the reference character 70. The switchcomprises aswitch casing 71 mounted on a gasket. 72 and attached to the housing bymeans of screws 73. 'A bracket 74 mounts a toggle switch arm 75 which ispivoted by means of a pin 76 to. the bracket. A projection 77 of thetoggle switch arm is attached to a link 78 bymeans of a pin 79. At theother end the link 78 is pivotally attached to a flange 80' of the yoke80 by means of a pin 81 A bolt 82 serves to interconnect opposite sidesof the link 78.

Coiled springs 83 and 84 engage at one end with the actuator 80 and atthe other ends respectively with plugs 65 and 66, the springs extendingthrough holes 85 in the gasket and holes 86 in the housing 25. Still.another plug 87 engages at one end with the yoke and at the other endwith the plug 68 and extends through a hole 88 in the gasket and asimilar hole 89 in the housing 25. Cooling holes 90 may be provided inthe toggle switch communicating with a chamber 91 therein to assist indissipating heat generated in the socket.

' In the operation of the device herein shown and described it iscustomary to first mount the incandescent lamp 10 in the socket bypressing the base 11 of the lamp downwardly within the area defined bythe brackets 26, 27 and 28 and. so that the prongs 12 and 13 extenddownwardly into the prong-receiving recesses 33 and 34 within thelinersin those recesses. At this point there will be but a loose conectionbecause the toggle switch'arm 75 will need to bein open or releasedposition. If it were in closed position, the liners would be pressed soclose together that the aperture formed between them would not be largeenough to admit the prongs. Once in place the prongs are clamped. Thisis accomplished by rotating the toggle switch arm 75 from open orunclamped position to closed or clamped position. This necessitates amovement clockwise as viewed in FiguresZ, 4, 7 and 8. As the switch armis swung in the direction described, pressure is exerted upon the link78 which moves the actuator 80 upwardly as viewed inthe figures madereference to.

Movement of the actuator as described causes pressure upon the springs83 and 84 which in turn press the plugs 65 and 66 into engagement withthe respective liners .44 and 51 This causes the liners to exert a tightphysical and electrical engagement with the respective plugs.

At initial stages of the engagement, as illustrated in Figure7, theactuator 80 will have moved plugs 87 and 68 inwardlyinto engagement withthe resilient armand will tend to tilt both the arm 60 and the resilientarm'61 about; a fulcrum 92 but the movement will not be far enough asyet to close contact between the resilient arm 61 and the switch contactplate 54. As the toggle switch am, however, is swung from theprong-engaging position shown in Figure -7 to the over-center-positionshown in Figure 8, the yoke or actuator 80 will be moved the additionaldistance necessary to shift plugs 87 and 68 far enough so that theresilient arm 61 is moved into contact with the switch contact plate 54.Since it will not be possible for electric current to flow through thebinding switch arm 61 and the switch contact plate 54, the circuit.

will be complete from the binding post 21 to theprong 13 and thereafterwhen the control switch 18 is turned to on position current will flow.It is important to note, however, that current cannot be made toflowsuntil after a tight physical and electrical contacthas been made"between the liners and the corresponding prongs. Hence there will be nopossibility of arcing and hence undesired pitting of the prongs by anyinadvertent act of the mechanic or operator.

Similarly when the prongs of the lamp 10-are to be released, rotation ofthe switch arm 75 in a reverse or counterclockwise direction, as viewedin Figures 2, 4, 7

and 8, first effects a disconnection of the resilient switchv arm 61from the switch contact plate 54, fliereby opening the circuit beforepressure is released upon the liners and their engagement with theprongs. Should, through some inadvertence, the current be left onthrough the control switch 18, again arcing will be avoided at theprongs and if any arcing takes, switch elements.

There has accordingly been shown and described herein a safety switchdevice which is compact in its construction and so designed that it canbe built into a socket of substantially the same design andconfiguration as sockets currently in use for incandescent lamps of thekind herein described. The parts are few in number and simply de. signedas shown so that operation is positiveand proof against arcing at theprongs either when the current is turned on or when the current isturned off.

While I have herein shown and described my invention in what I haveconceived to be the most practicalhand preferred embodiment, it isrecognized that departures may be made therefrom within the scope of myinvention; which is not to be limitedtothe details disclosed herein 7but is to be accorded the full scope of the claims soas to embrace anyand all equivalent devices.

Having described my invention, .what I claim as new and desire to secureby Letters Patent is: q 1" l. A clamp and switch device for a high powerprong contact incandescent lamp comprising a socket housing; mountingmeans of dielectric material secured inlthe housing having prongrecesses therein, matching: split prong contacting elements ofelectrically conducting material in said recesses, a pair of armaturesforming a. switch in said housing in circuit with one of said prongcontacting elements, one of said armatures comprising a resilient switcharm in the general path of movement of portions of said split prongcontacting elements movable to closed position upon:movement of saidportions to positions wherein said elements are in prong engagingposition, a pressure member having resilient engagement with said prongcontacting elements first and thereafter.

with one of said switch armatures, and an actuator on the.

housing having on and ofl positions and operably engageable with saidpressure member whereby to'move said prong engaging elements and saidswitch jointly between on and off positions.

2. A clamp and switch device for a high power prong. contactincandescent lamp comprising a socket housing,

' mounting means of dielectric material secured in the housing andhaving a plurality of prong recesses therein, a split prong contactingelement of electrically conducting mate rial in each prong, a pair ofarmatures forming a switc in said housing in circuit with one of saidprong contact-j ing elements, one of said armatures comprising a switcharm in the general path of movement of said prong can place it will beconfined to the tacting elements, said prong contacting elements havingpositions closed upon the prongs while said armatures remain in openposition, said prong contacting elements being movable to closedposition upon movement of portions of said elements to positions whereinsaid elements are in prong engaging position first followed by movementof said armatures to closed position, and a lever member mounted in thehousing in resilient engagement with said prong contacting elements andone of said switch armatures, said lever member having on and ofipositions whereby to move said prong engaging elements and said switchbetween on and off positions.

3. A clamp and switch device for a high power prong contact incandescentlamp comprising a socket housing, mounting means of dielectric materialsecured in the housing and having a plurality of prong recesses therein,a split prong contacting element of electrically conducting material ineach prong, a pair of armatures forming a switch in said housing incircuit with one of said prong contacting elements, one of saidarmatures comprising a switch arm in the general path of movement ofsaid prong contacting elements movable to closed position upon movementof portions of said elements to positions wherein said elements are inprong engaging position, and a lever member mounted in the housing inresilient engagement with said prong contacting elements and one of saidswitch armatures, said lever member having on and ofi positions wherebyto move said prong engaging elements and said switch between on and offpositions.

4. A clamp and switch device for a high power prong contact incandescentlamp comprising a socket housing, mounting means of dielectric materialsecured in the housing having prong recesses therein, matching splitprong contacting elements of electrically conducting material in saidrecesses, a pair of armatures forming a switch in said housing incircuit with one of said prong contacting elements, one of saidarmatures comprising a resilient switch arm in the general path ofmovement of portions of said split prong contacting elements movable toclosed position upon movement of said portions to positions wherein saidelements are in prong engaging position, a pressure member havingresilient engagement with said prong contacting elements and one of saidswitch armatures, and an actuator on the housing having on and offpositions and operably engageable with said pressure member whereby tomove said prong engaging elements and said switch jointly between on andoil positions.

5. A sequence clamp and switch device for a high power prong contactincandescent lamp comprising a socket housing, a pair of matching blocksof dielectric material mounted in the housing for limited lateralmovement and having a plurality of prong recesses therebetween, means ineach block forming matching half recesses of said plurality of prongrecesses, a matching prong contacting element of electrically conductingmaterial in each matching half recess in the blocks, a pair of armaturesforming a switch in said housing in circuit with one of said prongcontacting elements, one of said armatures comprising a resilient switcharm in the general path of movement of said prong contacting elementsmovable to closed position upon movement of said elements to positionswherein said elements are in prong engaging position, a resilientpressure member having resilient engagement with said matching prongcontacting elements and with one of said switch armatures, and anactuating member on the housing having on and off positions and operablyengageable with said pressure member whereby to move said prong engagingelements and said switch simultaneously between on and off positions.

6. A clamp and switch device for a high power prong contact incandescentlamp comprising a socket housing, a support of dielectric materialmounted in the housing having prong receiving recesses therein, a pairof metallic liner halves mounted for lateral movement in each recess andof radius less than the radius of the said recess, binding posts for therespective liners, one of said liners having a laterally extendingswitch contact, a resilient switch arm mounted in said housing forengagement with said switch plate, one of said blocks having transversepaths communicating respectively with each of the liners therein andhaving an intermediate transverse path therebetween, a plug in each saidaperture engageable respectively with the liners and said resilientswitch arm, an actuator for said plugs, resilient means between theactuator and the plugs having engagement with the liners, a toggleswitch on the housing comprising an arm having ofi and on positions, anda link between said arm and the actuator having an over-centeradjustment in on position whereby to move and hold said liners and saidresilient switch arm in on position.

7. A sequence clamp and switch device for a high power prong contactincandescent lamp comprising a socket housing, a pair of matching blocksof dielectric material mounted in the housing for limited lateralmovement, clamping means for said blocks, said blocks having prongreceiving recesses therebetween, comprising means in each block forminga matching half recess of each said recess, a metallic half linermounted for lateral movement in each matching half recess and of radiusless than the radius of the said half recess, binding posts for theliners in the respective prong receiving recesses, one of said linershaving a laterally extending switch contact plate, a resilient switcharm mounted in said housing for engagement with said switch plate, oneof said blocks having transverse apertures communicating respectivelywith each of the liners therein and having an intermediate transverseaperture therebetween, plugs of dielectric material in said firstidentified transverse apertures engageable respectively with the linersand a plug in the next identified aperture engageable with saidresilient switch arm after engagement of said first plugs with saidliners, an actuator for said plugs, resilient means between the actuatorand the plugs having engagement with the liners, a toggle switch on thehousing comprising an arm having ofi and on positions, and a linkbetween said arm and the actuator having an overcenter adjustment in onposition whereby to move and hold said liners and said resilient switcharm in on position.

8. A clamp and switch device for a switch operated high power prongcontact incandescent lamp comprising a socket housing, mounting means ofdielectric material secured in the housing having prong receivingrecesses therein, conforming split prong contacting elements ofelectrically conducting material in said recesses, a switch in saidhousing in circuit with one of said split prong contacting elements, andmanually actuated socket locking means for substantially immediatelyclamping said prong contacting elements about said prongs and thereafterclosing said switch, but upon release operating to immediately open saidswitch and thereafter release said clamping elements.

9. A clamp and switch device for a switch operated high power contactincandescent lamp comprising a socket housing, mounting means ofdielectric material secured in the housing having prong receivingrecesses therein, conforming split prong contacting elements ofelectricall'y conducting material in said recesses, a switch in saidhousing in circuit with one of said split prong contacting elements, andmanually actuated socket locking and release means including leveractuated mechanism for resiliently first clamping said conforming splitcontacting elements on said prongs and thereafter closing said switchbut upon release operating to immediately open said switch andthereafter release said clamping elements.

2,302,048 Park Nov. 17, 1942 Parish May 24, 1949

